$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\left({\mathrm{NO}}_2\right)}_2\right]\mathrm{Cl}$ exhibits

The given compound may have linkage isomerism due to presence of NO₂  group which may be in the form -NO₂  or ONO .
It may have ionisation isomerism due to presence of two ionisable group -NO₂ & -CI . It may have geometrical isomerism in the form of cis-trans form as follows

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4\mathrm{CI}\left({\mathrm{NO}}_2\right)\right]{\mathrm{NO}}_2\&\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\left({\mathrm{NO}}_2\right)}_2\right]\mathrm{CI}$ - ionisation isomers

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\left({\mathrm{NO}}_2\right)\right]\mathrm{CI}\&\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\left(\mathrm{ONO}\right)\right]\mathrm{CI}$ -   Linkage isomers